In many applications in machine tools or for ground working tools or for the fabrication of machine, vehicle and structural parts, it is desirable to make use of a composite construction of which a relatively massive member is constituted by a forging, especially a steel or alloy steel drop or die forging, and a metal plate which is welded to this forging.
For the most part, such elements have been fabricated by forging the massive part from a blank, billet or bloom of steel, removing any forging flash or fins which may be produced by the pressing of the material between the forging dies, positioning a surface of the forging with an edge of the plate, and welding the two together.
The welding operation may effect the contours of the forging in this case and the plate finishing of the forging prior to welding represents an expensive and time-consuming operation, especially where grinding is required for the removal of the flash or fin.
Furthermore, when the plate is welded directly to the body of the forging, significant stresses develop at the weld joint which cannot be absorbed by any resilience in the massive body of the forging so that premature rupture may be a danger. In any event, the connection between the plate and the forging has only limited ability to withstand stress, and especially alternate bending stress, which may lead to early fatigue.
Finally, because of the nature of the differences in the contours of the plate and the body of the forging at which the weld seam is to be produced, difficulties have been encountered in the automated production of the weld seam using welding robots and like automatons.